A mountain goat in Idaho's Snake River Range. (Idaho Department of Fish and Game / Courtesy)

Washington bighorns

There are about 1,700 wild bighorn sheep in 17 herds in central and eastern Washington. In March, Washington transported 20 bighorn sheep to Utah in an effort to keep the Chelan Butte Herd smaller in an effort to prevent respiratory diseases.

IDAHO FALLS – Just so you know, Wyoming Game and Fish doesn’t hate mountain goats. But the growth of the non-native critters in the Teton Range is posing a problem that has wildlife managers considering lethal measures.

An aerial count this past winter found, for the first time, invasive mountain goats outnumbering native bighorn sheep.

Wyoming Game and Fish biologist Aly Courtemanch counted 88 mountain goats to 81 bighorns. Some estimates put the goat numbers at 100. Grand Teton National Park is reviewing a plan it hopes to implement this year to remove the invaders, mostly by catching them alive or possibly shooting the hard-to-catch goats.

Why the bounty on mountain goats?

Four of Wyoming’s native bighorn sheep populations have been given highest priority, and wildlife managers hope to protect them from the threat of diseases from goats and domestic sheep where habitat overlaps. The other issue is that habitat in mountain country provides a limited amount of groceries that a small bighorn sheep herd can’t afford to share.

“Where we think that issue really becomes significant is on winter ranges,” said Doug McWhirter, Game and Fish wildlife management coordinator. “In the Tetons, those winter ranges are very restricted, high elevation, wind-blown areas and they don’t support a lot of mouths.

“It’s a situation where although we like mountain goats, this is a situation where with these high-priority sheep herds, we’re favoring bighorn sheep. We basically support the park service in the identification if this is an issue.”

Bighorn sheep once numbered in the millions across North America, but the population crashed in the early 1900s to several thousand due to diseases introduced by domestic sheep and by overhunting. Now bighorns are mostly confined to remote mountainous areas across the West. The national park plans to protect the bighorns that fall within park boundaries, and Game and Fish is backing it up by encouraging mountain goat hunting on the west side of the Tetons.

“What we are doing is we have created some new hunt areas in the Tetons and the Absarokas and initiated a whole new license type for mountain goats which allows us to much more liberally hunt those goats,” McWhirter said. “What we are looking to do is to minimize goat numbers in the Tetons.”

Game and Fish plans to issue 48 licenses to shoot goats west of the park this year.

He said another native bighorn herd under encroachment by mountain goats is around the northeast corner of Yellowstone National Park in the Absaroka Range.

McWhirter said the bighorn herd in the Tetons “is what we call the coordinative herd. It’s a population that has never been extricated, never been supplemented. It’s a native sheep herd and one of our highest-priority herds.”

Besides the threat of disease, bighorns also face fragmented habitat and being pushed into higher elevations with poorer conditions. Courtemanch told a public open house meeting on goat management that avalanches are a major cause of death for bighorns occurring at a higher rate than predation, according to a WyoFile report of the meeting.

That also brings up the pressure bighorns receive from backcountry skiers. A map of viable winter habitat south of Grand Teton National Park overlaid with skier and bighorn activity tracked by GPS devices on both groups showed few bighorns entered the skiers’ zone, according to research presented at the open house.

The mountain goat expansion into the park was decades in the making but has ballooned in recent years. Local biologists believe the goats migrated into the Tetons from a group established in the 1960s and 1970s in the Snake River Range of Idaho east of Palisades Reservoir. The goats were introduced into the area to give Idaho hunters a new critter to chase.

“That’s the most likely source for the goats in the park,” said Hollie Miyasaki, Idaho Department of Fish and Game bighorn sheep biologist. “The goats were introduced into Idaho; they moved into Wyoming. It’s probably likely that they moved from the Wyoming side north into the park.”

McWhirter said annual aerial goat counts conducted with Idaho Fish and Game puts estimates at 250 mountain goats in the Snake River Range and south of Teton Pass.

Occasional goats were seen in the park during the 1980s and ’90s. “But it wasn’t until 2008, when it was actually documented that there were nannies with kids,” McWhirter said. “So that population was reproducing. So in the last 10 years, we basically go from a sporadic observation of a single goat to a hundred goats. It’s a dramatic increase.”

Grand Teton National Park is reviewing public comment on its plan to remove mountain goats. Its next step is to publish findings and issue an environmental impact statement on its eradication plan.

“We probably won’t be doing anything until late summer,” said Denise Germann, park public information officer.

McWhirter said Wyoming hunters have benefited from having mountain goats in the region south of Teton Pass.

“It’s what we call the Palisades herd, and it’s one that we benefited from the transplant in Idaho,” he said. “Those goats moved into Wyoming and established a population, and we began hunting them 20 years ago. The point I’m trying to make is we do value those goats. We want to manage for a thriving goat population there for hunting and viewing opportunities. The issues for bighorn sheep don’t exist there. We have to make it really clear, we don’t hate mountain goats.”